[Scilab-users] color under a curve

[Adrien Vogt-Schilb]

On 13/03/2013 13:01, Adrien Vogt-Schilb wrote:
>
> Samuel once provided a solution to this: 
For the record: actually it was Antoine, and he provided a function.

Could still be deposited to fileexchange. Antoine would you allow your 
function to be posted? Do you happen to have a more recent version than 
the one you posted back in 2011:



Here is an example:

x=[-10:10];y1=x+10;y2=x.*x;
BetweenCurves(x,y1,y2);


Here is the source code below:


////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 

// Plot area between two curves
function [h,epoly,ey1,ey2]=BetweenCurves(x,y1,y2,varargin)
//
//      Plots two curves and fill the area in between
//
//      INPUTS:
//              x       vector (1,n) of horizontal coordinates
//              y1      vector (1,n) value of 1st curve y1(x)
//              y2      vector (1,n) value of 2nd curve y2(x)
//       -- optional inputs: pairs "keyword","value" --
//              "handle",h      handle to the graphic window to use
//              "axis",a      handle to the graphic axis to use
//              "foreground", colorid   id of the color to use for
painting the area
//              "background", colorid   id of the color to use for
curves stroke
//
//      OUTPUTS:
//              h       handle to the graphic window used
//              epoly   handle to the polygone that fill the area in 
between
//              ey1     handle to first curve
//              ey2     handle to second curve

//default values for optional argument
        hfig=-1;
        background=%nan;
        foreground=%nan;
// scan varargin for optional parameter pairs (they can appear in any 
order)
     for i=1:2:length(varargin)
        keyword=varargin(i);
        value=varargin(i+1);
        select keyword
           case "handle" then
              hfig=value;
              scf(hfig);
           case "axis" then
              axis=value;
              sca(axis);
              hfig=axis.parent;
           case "background" then
              background=value;
           case "foreground" then
              background=value;
        end
     end
// special treatment for handle (aka hack alert)
     if typeof(hfig) ~= "handle" then
        hfig=scf();
     end
     h=hfig;
     scf(hfig);
     xfpoly([x,x($:-1:1)],[y1,y2($:-1:1)]);
     epoly=gce();
     plot(x,y1);
     ey1=gce();
     plot(x,y2);
     ey2=gce();
// background setting
     if (~isnan(background)) then
        // optional background specified
        epoly.background=background;
     else
        // default background
        epoly.background=color("gray87");
     end
// foreground setting (as for background)
     if (~isnan(foreground)) then
        epoly.foreground=foreground;
        ey1.children.foreground=foreground;
        ey2.children.foreground=foreground;
     else
        epoly.foreground=color("gray65");
        ey1.children.foreground=color("gray65");
        ey2.children.foreground=color("gray65");
     end
endfunction
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 


-- 
Adrien Vogt-Schilb (Cired)
Tel: (+33) 1 43 94 73 83